The cellular communication technology has witnessed a gradual and increasing trend of using internal antennas instead of more conventional external antenna. Cellular communication also has experienced an increase and an enhanced emphasis on multi band and multi system capabilities of cellular handsets. These changes have caused a growing demand for single feed single and multi band internal antennas for system applications comprising both the cellular and non-cellular frequency bands, which include GPS and Bluetooth.
The Planar Inverted F-Antenna (PIFA) has proven to be a versatile choice as an internal antenna for the multi band and multi system antenna. However, the PIFA requires a relatively large volume of space in present compact wireless devices. Despite many improvements in PIFAs, the volume or amount of space the PIFA occupies continues to be a significant determining factor for its desirable performance.
In view of the emerging constraints on the available volume for internal antennas, there is a need to look for potentially more efficient planar antenna configurations.